Method of making glycerol

ABSTRACT

Method of producing glycerol that includes mixing a peroxide stream with an olefenic alcohol stream to form a feed stream; processing the feed stream in a high shear device to produce a high shear dispersion of peroxide and olefinic alcohol, wherein the high shear device is configured with a rotor and a stator separated by a shear gap; and contacting the high shear dispersion with a catalyst in a reactor to produce glycerol.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 12/144,440, filed Jun. 23, 2008, which applicationclaims the benefit under 35 U.S.C. §119(e) of U.S. Provisional PatentApplication No. 60/946,482, filed Jun. 27, 2007. The disclosure of eachapplication is hereby incorporated herein by reference in entirety forall purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

TECHNICAL FIELD

The invention generally relates to apparatus and methods for makingglycerol, and more particularly related to the acceleration of suchreactions by high shear mixing.

BACKGROUND OF THE INVENTION

Glycerol is one of the simplest trihydric alcohols, with the formulaCH₂OHCHOHCH₂OH. The name glycerol is preferred for the pure chemical,but the commercial product is usually called glycerin. It is widelydistributed in nature in the form of its esters, called glycerides. Theglycerides are the principal constituents of the class of naturalproducts known as fats and oils.

Glycerin is used in nearly every industry. With dibasic acids, such asphthalic acid, it reacts to make the important class of products knownas alkyl resins, which are widely used as coating and in paints. It isused in innumerable pharmaceutical and cosmetic preparations; it is aningredient of many tinctures, elixirs, cough medicines, and anesthetics;and it is a basic medium for toothpaste. In foods, it is an importantmoistening agent for baked goods and is added to candies and icings toprevent crystallization. It is used as a solvent and carrier forextracts and flavoring agents and as a solvent for food colors. Manyspecialized lubrication problems have been solved by using glycerin orglycerin mixtures. Many millions of pounds are used each year toplasticize various materials.

There are several routes to synthetic glycerine. One route involves fourprocess steps—the chlorination of propylene to allyl chloride, thechlorohydrination of allyl chloride to glycerol dichlorohydrins, thehydrolysis of the dichlorohydrins to epichlorohydrin, and the hydrolysisof epichlorohydrin to glycerine. A second route is based upon threeprocess steps—the oxidation of propylene to acrolein, the hydroxylationof acrolein to allyl alcohol, and the hydroxylation of allyl alcohol toglycerine. The third route also employs three steps—the epoxidation ofpropylene to propylene oxide, isomerization of propylene oxide to allylalcohol, and the hydroxylation of the allyl alcohol to glycerine. As canbe seen from the above, much work has been done in altering thechemistry of the reactions while little investigation has been done withregard improving the mixing of the reactants to accelerate the reactionrate.

Consequently, there is a need for simple accelerated methods for makingglycerol by improving the mixing of the olefinic alcohol and peroxide.

SUMMARY

Methods and systems for the hydroxylation of olefenic alcohols aredescribed herein. The methods and systems incorporate the novel use of ahigh shear device to promote mixing and solubility of peroxides with theolefenic alcohol. The high shear device may allow for lower reactiontemperatures and pressures and may also reduce hydroxylation time withexisting catalysts. Further advantages and aspects of the disclosedmethods and system are described below.

In an embodiment, a method of making glcyerol comprises introducing aperoxide into an olefenic alcohol stream to form a reactant stream. Themethod also comprises subjecting said reactant stream to a shear rate ofgreater than about 20,000 s⁻¹ with a high shear device. In addition, themethod comprises contacting the reactant stream with a catalyst tohydroxylate the olefenic alcohol and make glycerol.

In an embodiment, a system for the making glycerol comprises at leastone high shear device comprising a rotor and a stator. The rotor and thestator are separated by a shear gap in the range of from about 0.02 mmto about 5 mm. The shear gap is a minimum distance between the rotor andthe stator. The high shear mixing device is capable of producing a tipspeed of the at least one rotor of greater than about 23 m/s (4,500ft/min). In addition, the system comprises a pump configured fordelivering a liquid stream comprising liquid phase to the high shearmixing device. The system also comprises a reactor for hydroxylation ofan olefenic alcohol coupled to the high shear device. The reactor isconfigured for receiving a liquid reactant stream from the high sheardevice.

Embodiments of the disclosure pertain to a method of producing glycerolthat may include the steps of mixing a peroxide stream with an olefenicalcohol stream to form a feed stream; processing the feed stream in ahigh shear device to produce a high shear dispersion of peroxide andolefinic alcohol, wherein the high shear device may be configured with arotor and a stator separated by a shear gap; and contacting the highshear dispersion with a catalyst in a reactor to produce glycerol.

In aspects, the high shear dispersion may include bubbles with anaverage bubble diameter of less than about 5 microns. Olefinic alcoholin the high shear dispersion may be hydroxylated to produce glycerol. Inother aspects, wherein the peroxide stream may include hydrogenperoxide, ethylbenzyl hydroperoxide, t-butyl hydroperoxide, t-amylhydroperoxide, cumene hydroperoxide, 2-methyl-2-hydroperoxy-methylproprionate, 2-methyl-2-hydroperoxy propanoic acid,pyrrolehydroperoxide, furan hydroperoxide, 2-butylhydroperoxide,cyclohexyl hydroperoxide, and 1-phenyl-ethylhydroperoxide, orcombination thereof.

In yet other aspects, the olefenic alcohol stream may include allylalcohol, methallyl alcohol, cinnamyl alcohol, methyl vinyl carbinol,dimethyl allyl alcohol, oleyl alcohol, methyl vinyl carbinol, crotylalcohol, methyallyl alcohol, cyclohexenol, or combinations thereof.

The high shear device may be operable at a tip speed of at least about23 msec, and may produce a shear rate of greater than about 20,000 s⁻¹.In forming the dispersion the high shear device may have an energyexpenditure of at least about 1000 W/m³. In some aspects, the shear gapmay be in the range of from about 0.02 mm to about 5 mm. In otheraspects, the method may include introducing the high shear dispersion toa fixed bed containing additional catalyst. The catalyst may include ametal oxide, a tungstic catalyst, an osmium catalyst, formic acid,sulfonic acid, sulfuric acid, or combinations thereof. Each of the rotorand the stator may include a toothed surface.

Other embodiments of the disclosure pertain to a method of producingglycerol that may include mixing a peroxide stream with an olefenicalcohol stream to form a reactant stream; processing the reactant streamin a high shear device to produce a high shear dispersion comprisingperoxide and olefinic alcohol; and contacting the high shear dispersionwith a catalyst in a reactor to produce glycerol, wherein the reactormay be operable at a bulk reaction pressure of about 10 to about 60 atm,and a bulk reaction temperature of about 20° C. to about 80° C. Inaspects, the high shear device may be configured with a rotor and astator separated by a shear gap.

The high shear dispersion may include bubbles having an average bubblesize less than about 1.5 μm. The high shear dispersion may includebubbles with an average diameter of less than about 5 microns. Olefinicalcohol in the high shear dispersion may be hydroxylated to produceglycerol.

In aspects, the peroxide stream may include hydrogen peroxide,ethylbenzyl hydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide,cumene hydroperoxide, 2-methyl-2-hydroperoxy-methyl proprionate,2-methyl-2-hydroperoxy propanoic acid, pyrrolehydroperoxide, furanhydroperoxide, 2-butylhydroperoxide, cyclohexyl hydroperoxide, and1-phenyl-ethylhydroperoxide, or combination thereof. In other aspects,the olefenic alcohol stream may include allyl alcohol, methallylalcohol, cinnamyl alcohol, methyl vinyl carbinol, dimethyl allylalcohol, oleyl alcohol, methyl vinyl carbinol, crotyl alcohol,methyallyl alcohol, cyclohexenol, or combinations thereof.

The high shear device may be operable at a tip speed of at least about23 msec. The high shear device may produce a shear rate of greater thanabout 20,000 s⁻¹. In forming the dispersion, the high shear device mayoperate with an energy expenditure of at least about 1000 W/m³. Theshear gap may be in the range of from about 0.02 mm to about 5 mm.

The catalyst may include a metal oxide, a tungstic catalyst, an osmiumcatalyst, formic acid, sulfonic acid, sulfuric acid, or combinationsthereof.

In aspects, the high shear device may include at least two generators.In further aspects, the shear rate provided by one generator is greaterthan the shear rate provided by another generator.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter that form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand the specific embodiments disclosed may be readily utilized as abasis for modifying or designing other structures for carrying out thesame purposes of the present invention. It should also be realized bythose skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram of a process for making glycerol,according to certain embodiments of the invention.

FIG. 2 is a longitudinal cross-section view of a multi-stage high shearmixing device, as employed in an embodiment of the system of FIG. 1.

DETAILED DESCRIPTION

The disclosed methods and systems for the production of glycerol employa high shear mechanical device to provide rapid contact and mixing ofperoxide and alcohol in a controlled environment in the reactor/mixerdevice. In particular, embodiments of the systems and methods may beused in the production of alcohols from the hydroxylation of olefenicalcohols. Preferably, the method comprises a homogeneous phase reactionof liquid olefenic alcohol with a peroxide. The high shear devicereduces the mass transfer limitations on the reaction and thus increasesthe overall reaction rate.

Chemical reactions involving liquids, gases and solids rely on time,temperature, and pressure to define the rate of reactions. In caseswhere it is desirable to react two or more raw materials of differentphases (e.g., solid and liquid; liquid and gas; solid, liquid and gas),one of the limiting factors in controlling the rate of reaction involvesthe contact time of the reactants. In the case of heterogeneouslycatalyzed reactions there is the additional rate limiting factor ofhaving the reacted products removed from the surface of the catalyst toenable the catalyst to catalyze further reactants. Contact time for thereactants and/or catalyst is often controlled by mixing which providescontact with two or more reactants involved in a chemical reaction. Areactor assembly that comprises an external high shear mixing device ormixer as described herein makes possible decreased mass transferlimitations and thereby allows the reaction to more closely approachkinetic limitations. When reaction rates are accelerated, residencetimes may be decreased, thereby increasing obtainable throughput.Product yield may be increased as a result of the high shear system andprocess. Alternatively, if the product yield of an existing process isacceptable, decreasing the required residence time by incorporation ofsuitable high shear may allow for the use of lower temperatures and/orpressures than conventional processes.

System for Hydroxylation of Olefenic Alcohols.

A high shear hydroxylation system will now be described in relation toFIG. 1, which is a process flow diagram of an embodiment of a high shearsystem 100 for the production of glycerol via the hydroxylation ofolefenic alcohols. The basic components of a representative systeminclude external high shear device (HSD) 140, vessel 110, and pump 105.As shown in FIG. 1, the high shear device may be located external tovessel/reactor 110. Each of these components is further described inmore detail below. Line 121 is connected to pump 105 for introducing anolefenic alcohol reactant. Line 113 connects pump 105 to HSD 140, andline 118 connects HSD 140 to vessel 110. Line 122 is connected to line13 for introducing a peroxide stream with the olefenic alcohol stream.Line 117 is connected to vessel 110 for removal of unreacted olefenicalcohol, peroxides, and other reactants. Additional components orprocess steps may be incorporated between vessel 110 and HSD 140, orahead of pump 105 or HSD 140, if desired. High shear devices (HSD) suchas a high shear mixing device, or high shear mill, are generally dividedinto classes based upon their ability to mix fluids. Mixing is theprocess of reducing the size of inhomogeneous species or particleswithin the fluid. One metric for the degree or thoroughness of mixing isthe energy density per unit volume that the mixing device generates todisrupt the fluid particles. The classes are distinguished based ondelivered energy density. There are three classes of industrial mixershaving sufficient energy density to consistently produce mixtures oremulsions with particle or bubble sizes in the range of 0 to 50 microns.High shear mechanical devices include homogenizers as well as colloidmills.]

Homogenization valve systems are typically classified as high energydevices. Fluid to be processed is pumped under very high pressurethrough a narrow-gap valve into a lower pressure environment. Thepressure gradients across the valve and the resulting turbulence andcavitations act to break-up any particles in the fluid. These valvesystems are most commonly used in milk homogenization and can yieldaverage particle size range from about 0.01 μm to about 1 μm. At theother end of the spectrum are high shear device systems classified aslow energy devices. These systems usually have paddles or fluid rotorsthat turn at high speed in a reservoir of fluid to be processed, whichin many of the more common applications is a food product. These systemsare usually used when average particle, or bubble, sizes of greater than20 microns are acceptable in the processed fluid.

Between low energy-high shear devices and homogenization valve systems,in terms of the mixing energy density delivered to the fluid, arecolloid mills, which are classified as intermediate energy devices. Thetypical colloid mill configuration includes a conical or disk rotor thatis separated from a complementary, liquid-cooled stator by aclosely-controlled rotor-stator gap, which is maybe between 0.025 mm and10.0 mm. Rotors are usually driven by an electric motor through a directdrive or belt mechanism. Many colloid mills, with proper adjustment, canachieve average particle, or bubble, sizes of about 0.01 μm to about 25μm in the processed fluid. These capabilities render colloid millsappropriate for a variety of applications including colloid andoil/water-based emulsion processing such as that required for cosmetics,mayonnaise, silicone/silver amalgam formation, or roofing-tar mixing.

An approximation of energy input into the fluid (kW/L/min) can be madeby measuring the motor energy (kW) and fluid output (L/min). Inembodiments, the energy expenditure of a high shear mixing device isgreater than 1000 W/m³. In embodiments, the energy expenditure is in therange of from about 3000 W/m³ to about 7500 W/m³. The shear rategenerated in a high shear mixing device may be greater than 20,000 s⁻¹.In embodiments, the shear rate generated is in the range of from 20,000s⁻¹ to 100,000 s⁻¹.

Tip speed is the velocity (m/sec) associated with the end of one or morerevolving elements that is transmitting energy to the reactants. Tipspeed, for a rotating element, is the circumferential distance traveledby the tip of the rotor per unit of time, and is generally defined bythe equation V(m/sec)=π·D·n, where V is the tip speed, D is the diameterof the rotor, in meters, and n is the rotational speed of the rotor, inrevolutions per second. Tip speed is thus a function of the rotordiameter and the rotation rate. Also, tip speed may be calculated bymultiplying the circumferential distance transcribed by the rotor tip,2πR, where R is the radius of the rotor (meters, for example) times thefrequency of revolution (for example revolutions (meters, for example)times the frequency of revolution (for example revolutions per minute,rpm).

For colloid mills, typical tip speeds are in excess of 23 m/sec (4500ft/min) and can exceed 40 m/sec (7900 ft/min) For the purpose of thepresent disclosure the term ‘high shear’ refers to mechanicalrotor-stator devices, such as mills or mixers, that are capable of tipspeeds in excess of 5 m/sec (1000 ft/min) and require an externalmechanically driven power device to drive energy into the stream ofproducts to be reacted. A high shear mixing device combines high tipspeeds with a very small shear gap to produce significant friction onthe material being processed. Accordingly, a local pressure in the rangeof about 1000 MPa (about 145,000 psi) to about 1050 MPa (152,300 psi)and elevated temperatures at the tip of the shear mixer are producedduring operation. In certain embodiments, the local pressure is at leastabout 1034 MPa (about 150,000 psi).

Referring now to FIG. 1, there is presented a schematic diagram of ahigh shear mixing device 200. High shear mixing device 200 comprises atleast one rotor-stator combination. The rotor-stator combinations mayalso be known as generators 220, 230, 240 or stages without limitation.The high shear mixing device 200 comprises at least two generators, andmost preferably, the high shear mixing device comprises at least threegenerators.

The first generator 220 comprises rotor 222 and stator 227. The secondgenerator 230 comprises rotor 223, and stator 228; the third generatorcomprises rotor 224 and stator 229. For each generator 220, 230, 240 therotor is rotatably driven by input 250. The generators 220, 230, 240rotate about axis 260 in rotational direction 265. Stator 227 is fixablycoupled to the high shear mixing device wall 255.

The generators include gaps between the rotor and the stator. The firstgenerator 220 comprises a first gap 225; the second generator 230comprises a second gap 235; and the third generator 240 comprises athird gap 245. The gaps 225, 235, 245 are between about 0.025 mm (0.01in) and 10.0 mm (0.4 in) wide. Alternatively, the process comprisesutilization of a high shear mixing device 200 wherein the gaps 225, 235,245 are between about 0.5 mm (0.02 in) and about 2.5 mm (0.1 in). Incertain instances the gap is maintained at about 1.5 mm (0.06 in).Alternatively, the gaps 225, 235, 245 are different between generators220, 230, 240. In certain instances, the gap 225 for the first generator220 is greater than about the gap 235 for the second generator 230,which is greater than about the gap 245 for the third generator 240.

Additionally, the width of the gaps 225, 235, 245 may comprise a coarse,medium, fine, and super-fine characterization. Rotors 222, 223, and 224and stators 227, 228, and 229 may be toothed designs. Each generator maycomprise two or more sets of rotor-stator teeth, as known in the art.Rotors 222, 223, and 224 may comprise a number of rotor teethcircumferentially spaced about the circumference of each rotor. Stators227, 228, and 229 may comprise a number of stator teethcircumferentially spaced about the circumference of each stator. Therotor and the stator may be of any suitable size. In one embodiment, theinner diameter of the rotor is about 64 mm and the outer diameter of thestator is about 60 mm. In other embodiments, the inner diameter of therotor is about 11.8 cm and the outer diameter of the stator is about15.4 cm. In further embodiments, the rotor and stator may have alternatediameters in order to alter the tip speed and shear pressures. Incertain embodiments, each of three stages is operated with a super-finegenerator, comprising a gap of between about 0.025 mm and about 3 mm.When a feed stream 205 including solid particles is to be sent throughhigh shear mixing device 200, the appropriate gap width is firstselected for an appropriate reduction in particle size and increase inparticle surface area. In embodiments, this is beneficial for increasingcatalyst surface area by shearing and dispersing the particles.

High shear mixing device 200 is fed a reaction mixture comprising thefeed stream 205. Feed stream 205 comprises an emulsion of thedispersible phase and the continuous phase. Emulsion refers to aliquefied mixture that contains two distinguishable substances (orphases) that will not readily mix and dissolve together. Most emulsionshave a continuous phase (or matrix), which holds therein discontinuousdroplets, bubbles, and/or particles of the other phase or substance.Emulsions may be highly viscous, such as slurries or pastes, or may befoams, with tiny gas bubbles suspended in a liquid. As used herein, theterm “emulsion” encompasses continuous phases comprising gas bubbles,continuous phases comprising particles (e.g., solid catalyst),continuous phases comprising droplets of a fluid that is substantiallyinsoluble in the continuous phase, and combinations thereof.

Feed stream 205 may include a particulate solid catalyst component. Feedstream 205 is pumped through the generators 220, 230, 240, such thatproduct dispersion 210 is formed. In each generator, the rotors 222,223, 224 rotate at high speed relative to the fixed stators 227, 228,229. The rotation of the rotors pumps fluid, such as the feed stream205, between the outer surface of the rotor 222 and the inner surface ofthe stator 227 creating a localized high shear condition. The gaps 225,235, 245 generate high shear forces that process the feed stream 205.The high shear forces between the rotor and stator functions to processthe feed stream 205 to create the product dispersion 210. Each generator220, 230, 240 of the high shear mixing device 200 has interchangeablerotor-stator combinations for producing a narrow distribution of thedesired bubble size, if feedstream 205 comprises a gas, or globule size,if feedstream 205 comprises a liquid, in the product dispersion 210.

The product dispersion 210 of gas particles, or bubbles, in a liquidcomprises an emulsion. In embodiments, the product dispersion 210 maycomprise a dispersion of a previously immiscible or insoluble gas,liquid or solid into the continuous phase. The product dispersion 210has an average gas particle, or bubble, size less than about 1.5 μm;preferably the bubbles are sub-micron in diameter. In certain instances,the average bubble size is in the range from about 1.0 μm to about 0.1μm. Alternatively, the average bubble size is less than about 400 nm(0.4 μm) and most preferably less than about 100 nm (0.1 μm).

The high shear mixing device 200 produces a gas emulsion capable ofremaining dispersed at atmospheric pressure for at least about 15minutes. For the purpose of this disclosure, an emulsion of gasparticles, or bubbles, in the dispersed phase in product dispersion 210that are less than 1.5 μm in diameter may comprise a micro-foam. Not tobe limited by a specific theory, it is known in emulsion chemistry thatsub-micron particles, or bubbles, dispersed in a liquid undergo movementprimarily through Brownian motion effects. The bubbles in the emulsionof product dispersion 210 created by the high shear mixing device 200may have greater mobility through boundary layers of solid catalystparticles, thereby facilitating and accelerating the catalytic reactionthrough enhanced transport of reactants.

The rotor is set to rotate at a speed commensurate with the diameter ofthe rotor and the desired tip speed as described hereinabove. Transportresistance is reduced by incorporation of high shear mixing device 200such that the velocity of the reaction is increased by at least about5%. Alternatively, the high shear mixing device 200 comprises a highshear colloid mill that serves as an accelerated rate reactor (ARR). Theaccelerated rate reactor comprises a single stage dispersing chamber.The accelerated rate reactor comprises a multiple stage inline dispersercomprising at least 2 stages.

Selection of the high shear mixing device 200 is dependent on throughputrequirements and desired particle or bubble size in the outletdispersion 210. In certain instances, high shear mixing device 200comprises a Dispax Reactor® of IKA® Works, Inc. Wilmington, N.C. and APVNorth America, Inc. Wilmington, Mass. Model DR 2000/4, for example,comprises a belt drive, 4M generator, PTFE sealing ring, inlet flange 1″sanitary clamp, outlet flange ¾″ sanitary clamp, 2 HP power, outputspeed of 7900 rpm, flow capacity (water) approximately 300 l/h toapproximately 700 l/h (depending on generator), a tip speed of from 9.4m/s to about 41 m/s (about 1850 ft/min to about 8070 ft/min) Severalalternative models are available having various inlet/outletconnections, horsepower, nominal tip speeds, output rpm, and nominalflow rate.

Without wishing to be limited to a particular theory, it is believedthat the level or degree of high shear mixing is sufficient to increaserates of mass transfer and may also produce localized non-idealconditions that enable reactions to occur that would not otherwise beexpected to occur based on Gibbs free energy predictions. Localized nonideal conditions are believed to occur within the high shear mixingdevice resulting in increased temperatures and pressures with the mostsignificant increase believed to be in localized pressures. The increasein pressures and temperatures within the high shear mixing device areinstantaneous and localized and quickly revert back to bulk or averagesystem conditions once exiting the high shear mixing device. In somecases, the high shear mixing device induces cavitation of sufficientintensity to dissociate one or more of the reactants into free radicals,which may intensify a chemical reaction or allow a reaction to takeplace at less stringent conditions than might otherwise be required.Cavitation may also increase rates of transport processes by producinglocal turbulence and liquid micro-circulation (acoustic streaming).

Vessel.

Vessel or reactor 110 is any type of vessel in which a multiphasereaction can be propagated to carry out the above-described conversionreaction(s). For instance, a continuous or semi-continuous stirred tankreactor, or one or more batch reactors may be employed in series or inparallel. In some applications vessel 110 may be a tower reactor, and inothers a tubular reactor or multi-tubular reactor. A catalyst inlet line115 may be connected to vessel 110 for receiving a catalyst solution orslurry during operation of the system.

Vessel 110 may include one or more of the following components: stirringsystem, heating and/or cooling capabilities, pressure measurementinstrumentation, temperature measurement instrumentation, one or moreinjection points, and level regulator (not shown), as are known in theart of reaction vessel design. For example, a stirring system mayinclude a motor driven mixer. A heating and/or cooling apparatus maycomprise, for example, a heat exchanger. Alternatively, as much of theconversion reaction may occur within HSD 140 in some embodiments, vessel110 may serve primarily as a storage vessel in some cases. Althoughgenerally less desired, in some applications vessel 110 may be omitted,particularly if multiple high shear devices/reactors are employed inseries, as further described below.

Heat Transfer Devices.

In addition to the above-mentioned heating/cooling capabilities ofvessel 110, other external or internal heat transfer devices for heatingor cooling a process stream are also contemplated in variations of theembodiments illustrated in FIG. 1. Some suitable locations for one ormore such heat transfer devices are between pump 105 and HSD 140,between HSD 140 and vessel 110, and between vessel 110 and pump 105 whensystem 100 is operated in multi-pass mode. Some non-limiting examples ofsuch heat transfer devices are shell, tube, plate, and coil heatexchangers, as are known in the art.

Pumps.

Pump 105 is configured for either continuous or semi-continuousoperation, and may be any suitable pumping device that is capable ofproviding greater than 2 atm pressure, preferably greater than 3 atmpressure, to allow controlled flow through HSD 140 and system 100. Forexample, a Roper Type 1 gear pump, Roper Pump Company (Commerce Ga.)Dayton Pressure Booster Pump Model 2P372E, Dayton Electric Co (Niles,Ill.) is one suitable pump. Preferably, all contact parts of the pumpcomprise stainless steel. In some embodiments of the system, pump 105 iscapable of pressures greater than about 20 atm. In addition to pump 105,one or more additional, high pressure pump (not shown) may be includedin the system illustrated in FIG. 1. For example, a booster pump, whichmay be similar to pump 105, may be included between HSD 140 and vessel110 for boosting the pressure into vessel 110. As another example, asupplemental feed pump, which may be similar to pump 105, may beincluded for introducing additional reactants or catalyst into vessel110.

Production of Glycerol.

In operation for the hydroxylation of olefinic alcohols for theproduction of glycerol, respectively, the olefinic alcohol stream isintroduced into system 100 via line 122, and combined in line 113 with aperoxide stream to form a reactant stream. The peroxide may be anysuitable peroxide compounds as will be described in more detail below.Alternatively, the peroxide stream may be fed directly into HSD 140,instead of being combined with the liquid reactant (i.e., olefinicalcohol, peroxide) in line 113. Pump 105 is operated to pump the liquidreactants (olefinic alcohol, peroxide) through line 121, and to buildpressure and feed HSD 140, providing a controlled flow throughout highshear device (HSD) 140 and high shear system 100.

In a preferred embodiment, peroxide may continuously be fed into theolefinic alcohol stream 112 to form high shear device feed stream 113(e.g. reactant stream). In high shear device 140, olefenic alcohol and aperoxide are highly sheared such that nanobubbles and/or microbubblesare formed for superior dissolution of peroxide and the alcohol intosolution. Once mixed, the reactants may exit high shear device 140 athigh shear device outlet line 118. Stream 118 may optionally enterfluidized or fixed bed 142 in lieu of a slurry catalyst process.However, in a slurry catalyst embodiment, high shear outlet stream 118may directly enter hydroxylation reactor 110 for hydroxylation. Thereaction stream may be maintained at the specified reaction temperature,using cooling coils in the reactor 110 to maintain reaction temperature.Hydroxylation products (e.g. glycerol and/or polyols) may be withdrawnat product stream 116.

In an exemplary embodiment, the high shear device comprises a commercialdisperser such as IKA® model DR 2000/4, a high shear, three stagedispersing device configured with three rotors in combination withstators, aligned in series. The disperser is used to create reactionsolution in the liquid medium comprising the reactants. The rotor/statorsets may be configured as illustrated in FIG. 2, for example. Thecombined reactants enter the high shear device via line 113 and enter afirst stage rotor/stator combination having circumferentially spacedfirst stage shear openings. The coarse dispersion exiting the firststage enters the second rotor/stator stage, which has second stage shearopenings. The reduced bubble-size dispersion emerging from the secondstage enters the third stage rotor/stator combination having third stageshear openings. The dispersion exits the high shear device via line 118.In some embodiments, the shear rate increases stepwise longitudinallyalong the direction of the flow. For example, in some embodiments, theshear rate in the first rotor/stator stage is greater than the shearrate in subsequent stage(s). In other embodiments, the shear rate issubstantially constant along the direction of the flow, with the stageor stages being the same. If the high shear device includes a PTFE seal,for example, the seal may be cooled using any suitable technique that isknown in the art. For example, the reactant stream flowing in line 113may be used to cool the seal and in so doing be preheated as desiredprior to entering the high shear device.

The rotor of HSD 140 is set to rotate at a speed commensurate with thediameter of the rotor and the desired tip speed. As described above, thehigh shear device (e.g., colloid mill) has either a fixed clearancebetween the stator and rotor or has adjustable clearance. HSD 140 servesto intimately mix the peroxide and the reactant liquid (i.e., olefenicalcohol). In some embodiments of the process, the transport resistanceof the reactants is reduced by operation of the high shear device suchthat the velocity of the reaction (e.g. reaction rate) is increased bygreater than a factor of about 5. In some embodiments, the velocity ofthe reaction is increased by at least a factor of 10. In someembodiments, the velocity is increased by a factor in the range of about10 to about 100 fold. In some embodiments, HSD 140 delivers at least 300L/h with a power consumption of 1.5 kW at a nominal tip speed of atleast 4500 ft/min, and which may exceed 7900 ft/min (140 m/sec).Although measurement of instantaneous temperature and pressure at thetip of a rotating shear unit or revolving element in HSD 140 isdifficult, it is estimated that the localized temperature seen by theintimately mixed reactants may be in excess of 500° C. and at pressuresin excess of 500 kg/cm² under high shear conditions. The high shearmixing results in formation of micron or submicron-sized bubbles, whichmay be due to cavitation. In some embodiments, the resultant dispersionhas an average bubble size less than about 1.5 μm. Accordingly, thereactant stream exiting HSD 140 via line 118 comprises micron and/orsubmicron-sized gas bubbles. In some embodiments, the mean bubble sizeis in the range of about 0.4 μm to about 1.5 μm. In some embodiments,the mean bubble size is less than about 400 nm, and may be about 100 nmin some cases. In many embodiments, the microbubble dispersion is ableto remain dispersed at atmospheric pressure for at least 15 minutes.

Once sheared, the resulting reactant solution exits HSD 140 via line 118and feeds into vessel 110, as illustrated in FIG. 1. As a result of theintimate mixing of the reactants prior to entering vessel 110, asignificant portion of the chemical reaction may take place in HSD 140,with or without the presence of a catalyst. Accordingly, in someembodiments, reactor/vessel 110 may be used primarily for heating andseparation of volatile reaction products from the alcohol product.Alternatively, or additionally, vessel 110 may serve as a primaryreaction vessel where most of the glycerol product is produced.Vessel/reactor 110 may be operated in either continuous orsemi-continuous flow mode, or it may be operated in batch mode. Thecontents of vessel 110 may be maintained at a specified reactiontemperature using heating and/or cooling capabilities (e.g., coolingcoils) and temperature measurement instrumentation. Pressure in thevessel may be monitored using suitable pressure measurementinstrumentation, and the level of reactants in the vessel may becontrolled using a level regulator (not shown), employing techniquesthat are known to those of skill in the art. The contents are stirredcontinuously or semi-continuously. In some embodiments, more than onevessel 110 may be used to hydroxylate the olefenic alcohol. That is, thesystem 100 may comprise more than one reactor stage.

Commonly known hydroxylation reaction conditions may suitably beemployed as the conditions of the production of an alcohol byhydroxylating an olefenic alcohol by using the catalysts. There is noparticular restriction as to the reaction conditions. However, thepressure is selected usually within a range of from about atmosphericpressure to 100 atm, more preferably from 10 to 60 atm, and the reactiontemperature may be within a range of from about 5° C. to about 100° C.,alternatively from about 20° C. to about 80° C., alternatively fromabout 40° C. to about 60° C.

As mentioned above, any suitable unsaturated or olefenic alcohols may behydroxylated in conjunction with the disclosed methods and processes. Asused herein, an olefenic alcohol is any compound containing at least adouble bond and a primary hydroxyl group. The olefenic alcohol may bebranched, linear, or cyclic in structure. Examples of such alcoholsinclude without limitation, allyl alcohol, methallyl alcohol, cinnamylalcohol, methyl vinyl carbinol, dimethyl allyl alcohol, oleyl alcohol,methyl vinyl carbinol, crotyl alcohol, methyallyl alcohol, cyclohexenol,and the like.

The oxidant for the hydroxylation reaction may at least one organichydroperoxide. Conventional organohydroperoxides include those havingthe formula: ROOH, where R may be hydrogen or a substituted orunsubstituted: alkyl, typically about C₃ to about C₂₀, preferably aboutC₃ to about C₁₀, most preferably about C₃ to about C₆ alkyl; aryl,typically C₆ to C₁₄, preferably C₆ to C.sub.10, most preferably C₆ aryl;aralkyl and alkaryl wherein the aryl and alkyl groups thereof are asdefined immediately above; cycloalkyl, typically about C₄ to about C₂₀,preferably about C₄ to about C₁₀, most preferably about C₄ to about C₈cycloalkyl; as well as oxacyclic having 1 to about 5 oxygens andpreferably 3 to about 20 carbons, and azacyclic having 1 to about 5nitrogens and preferably about 3 to about 20 carbons; and wherein thesubstituents of said R group include halogen, hydroxyl, ester and ethergroups.

Representative examples of suitable organohydroperoxides includeethylbenzyl hydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide,cumene hydroperoxide, 2-methyl-2-hydroperoxy-methyl proprionate,2-methyl-2-hydroperoxy propanoic acid, pyrrolehydroperoxide, furanhydroperoxide, 2-butylhydroperoxide, cyclohexyl hydroperoxide, and1-phenyl-ethylhydroperoxide.

Catalyst.

If a catalyst is used to promote the hydroxylation reaction, it may beintroduced into the vessel via line 115, as an aqueous or nonaqueousslurry or stream. Alternatively, or additionally, catalyst may be addedelsewhere in the system 100. For example, catalyst slurry may beinjected into line 121. In some embodiments, line 121 may contain aflowing recycle stream containing peroxide and/or olefenic alcohol fromvessel 110.

In embodiments, any catalyst suitable for catalyzing a hydroxylationreaction may be employed. Suitable catalysts may be any of the catalystsnormally used for hydroxylation of olefins. The catalysts may comprisetransition metals such as without limitation, transition metals such aszirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten,rhenium and uranium. Examples of suitable catalysts include withoutlimitation, a metal oxide such as tungsten oxide or molybdenum oxide, atungstic catalyst, osmium catalysts, formic acid, sulfonic acid,sulfuric acid, or combinations thereof. Further examples of suitablecatalysts include without limitation, selenotungstic acid, sulfotungsticacid, molybdotungstic acid, tungstic acid, molybdenum naphthenate,molybdenum hexacarbonyl, phosphomolybdic acid, molybdenum trioxide,titanium naphthenate, tungsten carbonyl, rhenium heptoxide, columbiumnaphthenate, tetrabutyl titanate, a mixture of molybdenum naphthenateand sodium naphthenate, tungstic oxide, sodium tungstate.

The bulk or global operating temperature of the reactants is desirablymaintained below their flash points. In some embodiments, the operatingconditions of system 100 comprise a temperature in the range of fromabout 10° C. to about 300° C. In specific embodiments, the reactiontemperature in vessel 110, in particular, is in the range of from about20° C. to about 100° C. In some embodiments, the reaction pressure invessel 110 is in the range of from about 1 atm to about 50 atm.

The reactant stream may be further processed prior to entering vessel110 (as indicated by arrow 18), if desired. In vessel 110, olefenicalcohol hydroxylation occurs via catalytic hydroxylation. The contentsof the vessel are stirred continuously or semi-continuously, thetemperature of the reactants is controlled (e.g., using a heatexchanger), and the fluid level inside vessel 110 is regulated usingstandard techniques. Olefenic alcohol hydroxylation may occur eithercontinuously, semi-continuously or batch wise, as desired for aparticular application. Any by-products that are produced may exitreactor 110 via line 117. This stream may comprise unreacted alcohol,and peroxides, for example. The unconverted reactants and/or byproductsremoved via line 117 may be further treated, and the components may berecycled, as desired. In a specific embodiment, unconverted olefenicalcohol from vessel 110 may be recycled back to line 121 through line120.

The reaction product stream including unconverted peroxide and/orolefenic alcohol and corresponding byproducts exits vessel 110 by way ofline 116. The glycerol product may be recovered and treated as known tothose of skill in the art.

Multiple Pass Operation.

In the embodiment shown in FIG. 1, the system is configured for singlepass operation, wherein the output from vessel 110 goes directly tofurther processing for recovery of alcohol product. In some embodimentsit may be desirable to pass the contents of vessel 110, or a liquidfraction containing unreacted olefenic alcohol, through HSD 140 during asecond pass. In this case, line 117 is connected to line 121 via dottedline 120, and the recycle stream from vessel 110 is pumped by pump 105into line 113 and thence into HSD 140. Additional peroxide stream may beinjected via line 122 into line 113, or it may be added directly intothe high shear device (not shown).

Multiple High Shear Mixing Devices.

In some embodiments, two or more high shear devices like HSD 140, orconfigured differently, are aligned in series, and are used to furtherenhance the reaction. Their operation may be in either batch orcontinuous mode. In some instances in which a single pass or “oncethrough” process is desired, the use of multiple high shear mixingdevices in series may also be advantageous. In some embodiments wheremultiple high shear mixing devices are operated in series, vessel 110may be omitted. In some embodiments, multiple high shear mixing devices140 are operated in parallel, and the outlet dispersions therefrom areintroduced into one or more vessel 110.

While embodiments of the invention have been shown and described,modifications thereof can be made by one skilled in the art withoutdeparting from the spirit and teachings of the invention. Theembodiments described herein are exemplary only, and are not intended tobe limiting. Many variations and modifications of the inventiondisclosed herein are possible and are within the scope of the invention.Where numerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations. Use of broader terms such as comprises, includes,having, etc. should be understood to provide support for narrower termssuch as consisting of, consisting essentially of, comprisedsubstantially of, and the like. Accordingly, the scope of protection isnot limited by the description set out above but is only limited by theclaims which follow, that scope including all equivalents of the subjectmatter of the claims. Each and every original claim is incorporated intothe specification as an embodiment of the invention. Thus, the claimsare a further description and are an addition to the preferredembodiments of the present invention. The disclosures of all patents,patent applications, and publications cited herein are herebyincorporated by reference, to the extent they provide exemplary,procedural or other details supplementary to those set forth herein.

1. A method of producing glycerol comprising: mixing a peroxide streamwith an olefenic alcohol stream to form a feed stream; processing thefeed stream in a high shear device to produce a high shear dispersion ofperoxide and olefinic alcohol, wherein the high shear device isconfigured with a rotor and a stator separated by a shear gap; andcontacting the high shear dispersion with a catalyst in a reactor toproduce glycerol.
 2. The method of claim 1, wherein the high sheardispersion comprises bubbles with an average bubble diameter of lessthan about 5 microns, and wherein olefinic alcohol in the high sheardispersion is hydroxylated to produce glycerol.
 3. The method of claim1, wherein the peroxide stream comprises hydrogen peroxide, ethylbenzylhydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide, cumenehydroperoxide, 2-methyl-2-hydroperoxy-methyl proprionate,2-methyl-2-hydroperoxy propanoic acid, pyrrolehydroperoxide, furanhydroperoxide, 2-butylhydroperoxide, cyclohexyl hydroperoxide, and1-phenyl-ethylhydroperoxide, or combination thereof.
 4. The method ofclaim 3, wherein the olefenic alcohol stream comprises allyl alcohol,methallyl alcohol, cinnamyl alcohol, methyl vinyl carbinol, dimethylallyl alcohol, oleyl alcohol, methyl vinyl carbinol, crotyl alcohol,methyallyl alcohol, cyclohexenol, or combinations thereof.
 5. The methodof claim 4, wherein the high shear device is operable at a tip speed ofat least about 23 msec, and produces a shear rate of greater than about20,000 s⁻¹.
 6. The method of claim 1, wherein forming the dispersioncomprises an energy expenditure of at least about 1000 W/m³, and whereinthe shear gap is in the range of from about 0.02 mm to about 5 mm
 7. Themethod of claim 6, further comprising introducing the high sheardispersion to a fixed bed containing additional catalyst.
 8. The methodof claim 1, wherein the catalyst comprises a metal oxide, a tungsticcatalyst, an osmium catalyst, formic acid, sulfonic acid, sulfuric acid,or combinations thereof.
 9. The method of claim 8, wherein each of therotor and the stator comprise a toothed surface.
 10. A method ofproducing glycerol comprising: mixing a peroxide stream with an olefenicalcohol stream to form a reactant stream; processing the reactant streamin a high shear device to produce a high shear dispersion comprisingperoxide and olefinic alcohol, wherein the high shear device isconfigured with a rotor and a stator separated by a shear gap; andcontacting the high shear dispersion with a catalyst in a reactor toproduce glycerol, wherein the reactor is operable at a bulk reactionpressure of about 10 to about 60 atm, and a bulk reaction temperature ofabout 20° C. to about 80° C.
 11. The method of claim 10, wherein thehigh shear dispersion comprises bubbles having an average bubble sizeless than about 1.5 μm.
 12. The method of claim 10, wherein the highshear dispersion comprises bubbles with an average diameter of less thanabout 5 microns, and wherein olefinic alcohol in the high sheardispersion is hydroxylated to produce glycerol.
 13. The method of claim12, wherein the peroxide stream comprises hydrogen peroxide, ethylbenzylhydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide, cumenehydroperoxide, 2-methyl-2-hydroperoxy-methyl proprionate,2-methyl-2-hydroperoxy propanoic acid, pyrrolehydroperoxide, furanhydroperoxide, 2-butylhydroperoxide, cyclohexyl hydroperoxide, and1-phenyl-ethylhydroperoxide, or combination thereof.
 14. The method ofclaim 13, wherein the olefenic alcohol stream comprises allyl alcohol,methallyl alcohol, cinnamyl alcohol, methyl vinyl carbinol, dimethylallyl alcohol, oleyl alcohol, methyl vinyl carbinol, crotyl alcohol,methyallyl alcohol, cyclohexenol, or combinations thereof.
 15. Themethod of claim 10, wherein the high shear device is operable at a tipspeed of at least about 23 msec, and produces a shear rate of greaterthan about 20,000 s⁻¹.
 16. The method of claim 15, wherein forming saiddispersion comprises an energy expenditure of at least about 1000 W/m³,and wherein the shear gap is in the range of from about 0.02 mm to about5 mm
 17. The method of claim 10, wherein the catalyst comprises a metaloxide, a tungstic catalyst, an osmium catalyst, formic acid, sulfonicacid, sulfuric acid, or combinations thereof.
 18. The method of claim10, wherein the shear gap is in the range of from about 0.02 mm to about5 mm, and wherein the high shear device is capable of producing a tipspeed of the at least one rotor of greater than about 23 m/s (4,500ft/min).
 19. The system of claim 18, wherein the high shear devicecomprises at least two generators.
 20. The system of claim 19, whereinthe shear rate provided by one generator is greater than the shear rateprovided by another generator.